Optical positioning device using telecentric imaging
First Claim
1. An optical displacement sensor for sensing movement of a data input device across a surface by determining displacement of optical features in a succession of frames, the sensor comprising:
- an illuminator comprising a coherent light source configured to illuminate a portion of the surface, with illumination having a substantially planar phase front before impinging upon the surface;
object-side telecentric imaging optics configured to image the optical features comprising a speckle pattern emanating from the illuminated portion of the surface;
an array of photosensitive elements configured to detect intensity data relating to the optical features imaged by the object-side telecentric imaging optics; and
wherein the speckle pattern imaged by the object-side telecentric imaging optics is imaged with reduced speckle boiling during translation of the surface with respect to the data input device.
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Abstract
One embodiment relates to an optical displacement sensor for sensing movement of a data input device across a surface by determining displacement of optical features in a succession of frames. The sensor includes at least an illuminator, telecentric imaging optics on the object (scattering surface) side, and an array of photosensitive elements. The illuminator is configured to illuminate a portion of the surface. The telecentric imaging optics is configured to image the optical features emanating from the illuminated portion of the surface, and the array of photosensitive elements is configured to detect intensity data relating to the optical features imaged by the telecentric imaging optics. Other embodiments are also disclosed.
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Citations
19 Claims
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1. An optical displacement sensor for sensing movement of a data input device across a surface by determining displacement of optical features in a succession of frames, the sensor comprising:
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an illuminator comprising a coherent light source configured to illuminate a portion of the surface, with illumination having a substantially planar phase front before impinging upon the surface; object-side telecentric imaging optics configured to image the optical features comprising a speckle pattern emanating from the illuminated portion of the surface; an array of photosensitive elements configured to detect intensity data relating to the optical features imaged by the object-side telecentric imaging optics; and wherein the speckle pattern imaged by the object-side telecentric imaging optics is imaged with reduced speckle boiling during translation of the surface with respect to the data input device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 16, 19)
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13. A method of sensing movement of a data input device across a surface, the method comprising:
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illuminating a portion of the surface with illumination having a substantially planar phase front before impinging upon the surface; mapping images of optical features comprising a speckle pattern from the illuminated portion of the surface to an array of photosensitive elements using telecentric imaging optics on an object side; and determining displacement of optical features emanating from the illuminated portion of the surface in a succession of frames to sense movement of the data input device across the surface in at least one dimension; and wherein the telecentric imaging optics images the optical features emanating from the surface with reduced speckle boiling during the movement of the data input device across the surface.
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14. An optical positioning device comprising:
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a laser configured to illuminate a portion of the surface, with illumination having a substantially planar phase front before impinging upon the surface; an array of photosensitive elements; telecentric imaging optics on an object side configured to focus a speckle pattern from the illuminated portion of the surface to the array of photosensitive elements; a signal processor configured to determine displacement of the speckle pattern in a succession of frames; and wherein the speckle pattern imaged by the telecentric imaging optics is imaged with reduced speckle boiling during translation of the surface with respect to the optical positioning device. - View Dependent Claims (15, 17, 18)
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Specification